Recently, single site catalysts have been developed to prepare olefin polymers. Typically, single site catalysts are metallocenes, organometallic coordination complexes containing one or more .pi.-bonded moieties in association with a metal atom from Groups IIIB to VIII or the Lanthanide series of the Periodic Table of Elements. Catalyst compositions containing single site catalysts are reportedly highly useful in the preparation of polyolefins, producing homogeneous polymers at excellent polymerization rates and allowing one to tailor closely the final properties of the polymer as desired.
European Patent Application Nos. 0 586 167 A1 and 0 586 168 A1 relate to polyolefin catalyst compositions comprising metallocene complexes of the formula ##STR2## wherein R is a hydrocarbyl optionally containing oxygen, silicon, phosphorous, nitrogen, or boron atoms, X is an organic group containing a cyclopentadienyl nucleus, M is a Group IVA metal, Y is a univalent anionic ligand, and Z is a bridging group. According to these applications, at least one R group must contain a polymerizable group, preferably containing at least three carbon atoms. Preferred metallocene complexes are zirconium complexes in which the polymerizable group is vinyl. Compounds such as ##STR3## are disclosed.
German Patent Application No. 3840772 A1 relates to metallocene catalyst components for use in polymerizing olefins prepared by reacting a zirconium, titanium, or hafnium metallocene compound with a poly(methhydrogen-siloxane) in the presence of a hydrosilation catalyst. Compounds such as ##STR4## are disclosed.
A new single site, olefin polymerization catalyst composition is described herein having good polymerization activity and productivity, which is easily and inexpensively prepared. The catalyst composition comprises the reaction product of 1) a conjugated allyl-cycloalkadienyl dianion catalyst precursor, 2) a compound comprising a metal from Groups IIIB to VIII or the Lanthanide series, and 3) an activating cocatalyst.